Libguestfs - Apr 2022 - Virt-install, virt-customize, virt-builder

On Mon, Apr 25, 2022 at 04:40:15PM +0200, Nguetchouang Ngongang Kevin
wrote:
> I want to achieve the external data file creation
> 
> "qemu-img create -o data_file_raw=on,data_file=path/to/file"
> 
> but there is no way to specify those options while using virt-builder.
Interesting - I had no idea about this feature before.

At the moment it's not possible to do this within virt-builder,
without patching virt-builder.  I guess maybe you can post-convert the
file after virt-builder has run?

I grepped the source of virt-install and it doesn't seem like it has
support either.  Nor does libvirt.

It should be possible to use virt-customize on these special qcow2
files, although I didn't try it.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW

Unfortunetaly i tried this before send these mails, 

The fact is that the qcow2 format don't permit to convert a file with
this option, that's why i wanted to build the image directly including
these options.

---
Nguetchouang Ngongang Kevin
ENS de Lyon
https://perso.ens-lyon.fr/kevin.nguetchouang/ 

Le 2022-04-25 17:11, Richard W.M. Jones a ?crit :
> On Mon, Apr 25, 2022 at 04:40:15PM +0200, Nguetchouang Ngongang Kevin
wrote:
> 
>> I want to achieve the external data file creation
>> 
>> "qemu-img create -o data_file_raw=on,data_file=path/to/file"
>> 
>> but there is no way to specify those options while using virt-builder.
> 
> Interesting - I had no idea about this feature before.
> 
> At the moment it's not possible to do this within virt-builder,
> without patching virt-builder.  I guess maybe you can post-convert the
> file after virt-builder has run?
> 
> I grepped the source of virt-install and it doesn't seem like it has
> support either.  Nor does libvirt.
> 
> It should be possible to use virt-customize on these special qcow2
> files, although I didn't try it.
> 
> Rich.
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On Mon, Apr 25, 2022 at 04:11:59PM +0100, Richard W.M. Jones
wrote:
> On Mon, Apr 25, 2022 at 04:40:15PM +0200, Nguetchouang Ngongang Kevin
wrote:
> > I want to achieve the external data file creation
> > 
> > "qemu-img create -o data_file_raw=on,data_file=path/to/file"
> > 
> > but there is no way to specify those options while using virt-builder.
> 
> Interesting - I had no idea about this feature before.
> 
> At the moment it's not possible to do this within virt-builder,
> without patching virt-builder.  I guess maybe you can post-convert the
> file after virt-builder has run?
> 
> I grepped the source of virt-install and it doesn't seem like it has
> support either.  Nor does libvirt.
> 
> It should be possible to use virt-customize on these special qcow2
> files, although I didn't try it.
I talked to Kevin and apparently this feature was added to qemu to
support a particular downstream project (oVirt), but in the end they
didn't use it and also support was never added to libvirt.  So it
doesn't particularly sound like this is a well tested or widely used
feature ...

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html